Genetic Association between Granites and Mineralization at the Gindi Akwati Cassiterite–Sulfide Deposit, North-Central Nigeria: Insights from Mineralogy, Fluid Inclusions, and Sulfur Isotopes

The cassiterite–sulfide mineralization occurs within quartz veins and greisenized Precambrian Older Granite around the Gindi Akwati region at Ropp complex’s western boundary, north-central Nigeria. intrusion of Jurassic Younger granite porphyry sheared marginal parts mylonitized zone created pathways for fluids that escaped during late-stage consolidation biotite granite. granites are highly differentiated (K/Rb < 200), peraluminous (A/CNK > 1), high-K, have high Sn concentrations (average = 117 ppm). forced interaction with ore-bearing fluid from under low oxygen fugacity or below NNO buffer. above fluid–rock caused mass changes in host greisenization redistributed ores vicinity shears. This suggests chloride ions take form significant complex-forming ligands efficiently sequestrate, transport, deposit ore metals (Sn, Zn, Fe, Cu) locally veins. redox potential probably gave a false impression metal zoning relatively higher abundance oxide than sulfides surface. alteration mineralogy (quartz-, topaz-, lepidolite-, fluorite-bearing assemblages) coupled S isotope inclusion systematic data hydrothermal history “greisens” started hot (homogenization temperature ≥300 °C), to moderate salinity 4.08 wt. % NaCl), density (≤0.6 g/cm3) ≥ 200 bar trapping pressure. sulfide isotopic composition (δ34SV-CDT −1.30 + 0.87 ‰) is very similar typical magmatic fluids, indicating late-magmatic early post-magmatic models related anorogenic intrusions.